Impact of Calcium and Two Doses of Vitamin D on Bone Metabolism in the Elderly: A Randomized Controlled Trial
What this study found
Higher-dose vitamin D increased serum 25OHD more than the 600 IU/day regimen, but it did not improve overall skeletal outcomes. At 12 months, 25OHD rose to 36.0 ± 9.7 ng/ml in the high-dose group versus 25.9 ± 6.9 ng/ml in the low-dose group, with a larger percent increase in the high-dose arm (95.5 ± 91.8 vs 44.0 ± 58.22; p < 0.0001). Calcium, creatinine, phosphorus, 1,25(OH)2D, PTH, osteocalcin, and Cross Laps showed no meaningful between-group advantage, and BMD at the total hip, femoral neck, and lumbar spine was not superior with the higher dose. The only skeletal signal was a small…
- Study & population
- Randomized controlled trial in ambulatory overweight adults aged 65 years or older with vitamin D insufficiency (screening 25OHD 10 to 30 ng/ml) recruited from three centers in greater Beirut, Lebanon.
- Intervention
- Both groups received calcium citrate tablets orally for 12 months, 4 tablets/day providing 1000 mg elemental calcium and 500 IU vitamin D3 daily.
- Key limitation
- Follow-up was limited to 12 months, so fracture outcomes and longer-term skeletal effects were not assessed.
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Open PDFOriginal abstract
The optimal dose of vitamin D to optimize bone metabolism in the elderly is unclear. We tested the hypothesis that vitamin D, at a dose higher than recommended by the Institute of Medicine (IOM), has a beneficial effect on bone remodeling and mass. In this double‐blind trial we randomized 257 overweight elderly subjects to receive 1000 mg of elemental calcium citrate/day, and the daily equivalent of 3750 IU/day or 600 IU/day of vitamin D3 for 1 year. The subjects’ mean age was 71 ± 4 years, body mass index 30 ± 4 kg/m2, 55% were women, and 222 completed the 12‐month follow‐up. Mean serum 25 hydroxyvitamin D (25OHD) was 20 ng/mL, and rose to 26 ng/mL in the low‐dose arm, and 36 ng/mL in the high‐dose arm, at 1 year (p < 0.05). Plasma parathyroid hormone, osteocalcin, and C‐terminal telopeptide (Cross Laps) levels decreased significantly by 20% to 22% in both arms, but there were no differences between the two groups for any variable, at 6 or 12 months, with the exception of serum calcitriol, which was higher in the high‐dose group at 12 months. Bone mineral density (BMD) increased significantly at the total hip and lumbar spine, but not the femoral neck, in both study arms, whereas subtotal body BMD increased in the high‐dose group only, at 1 year. However, there were no significant differences in percent change BMD between the two study arms at any skeletal site. Subjects with serum 25OHD <20 ng/mL and PTH level >76 pg/mL showed a trend for higher BMD increments at all skeletal sites, in the high‐dose group, that reached significance at the hip. Adverse events were comparable in the two study arms. This controlled trial shows little additional benefit in vitamin D supplementation at a dose exceeding the IOM recommendation of 600 IU/day on BMD and bone markers, in overweight elderly individuals. © 2017 American Society for Bone and Mineral Research.